The present invention relates generally to a surgical apparatus and method for performing less-invasive surgical procedures, and more specifically, to a surgical apparatus and method for performing a surgical procedure on the beating heart, such as stabilizing a portion of a beating heart during a coronary artery revascularization, wherein said surgical procedure is performed through a percutaneous transabdominal approach.
Cardiac surgery, and more specifically traditional coronary artery bypass graft (CABG) surgery, has been performed since the 1970""s on a regular basis with the advent of the cardio-pulmonary machine. In traditional CABG, the patient""s heart is exposed by cutting through the patient""s sternum and retracting the two halves of the ribcage. The heart is subsequently stopped while the blood continues to be pumped and oxygenated outside the body through extracorporeal circulation (ECC). The development of the cardio-pulmonary machine for ECC enables surgical interventions to take place on an arrested heart. This allows the surgeon to manipulate and operate on a perfectly still heart. As such, the arrested heart may be positioned to expose and provide the best access to the target artery requiring a bypass grafting.
However, there are two main invasive aspects associated to traditional CABGxe2x80x94the sternotomy incision and the ECC. Even with the constant technological improvements achieved during the last twenty-five years, the advantages offered with ECC have been at times offset by the morbidity (complications) and mortality related to the ECC itself. ECC has been documented to produce some well-known complications. Adverse effects associated with its use continue to be discovered and as such, ECC represents one of the most invasive clinical aspect associated with traditional CABG surgery. The inflammatory response, as well as the systemic microembolisms generated by ECC, induce to some extent a dysfunctional state of the brain, lungs, and kidneys, which tends to increase with the aging of the patient. Furthermore, evidence suggests that when ECC can be avoided, the left ventricular function (pumping efficiency) of the heart is better preserved, thereby also reducing the risks of post-operative complications and the need for ventricular assist devices to wean the arrested heart back to normal function. In addition to being one of the most invasive aspects of traditional CABG, ECC is also responsible for a large percentage of the initial procedure cost of traditional CABG. If ECC-related complications develop, ECC is also responsible for the post-operative costs incurred to treat these complications.
A median sternotomy, although less clinically-invasive than ECC, has the perception of being more invasive due to the surgical scaring that results from the surgery. A full median sternotomy may result in a temporary disturbance in the respiratory mechanism, an increased risk of operative shock or dehiscence, and re-operation surgery from bleeding complications. Moreover, prolonged exposure to air of the exposed mediastinum may lead to hypothermia, infection or compromise of the neuro-endocrine response. Patients with severe chronic obstructive pulmonary disease (COPD), severe emphysema or severe pulmonary insufficiency are therefore at a higher risk of developing complications when exposed to a sternotomy incision.
Port access surgery, developed largely by Heartport Inc. of Redwood City, Calif., consists of replacing the full median sternotomy by a series of intercostal port incision in the patient""s chest, through which coronary artery revascularization is performed. However, the most invasive aspect, ECC, is retained in this type of surgery. The patient""s heart is arrested by occluding the patient""s aorta preferably between the coronary arteries and the brachiocephalic artery with an expandable balloon on the distal end of an endovascular catheter which may be introduced via a femoral artery. Cardioplegic fluid is then delivered to the patient""s myocardium through a lumen in the same catheter or through a separate catheter positioned in the coronary sinus. A series of cannulae and catheters are usually employed to divert the patient""s blood flow to the cardio-pulmonary machine and to return the oxygenated blood to the circulatory system while the aorta remains occluded to avoid backflow into the heart chambers and surgical field. The port access approach most often also requires lung deflation in order to improve the access to remote territories of the heart, such as the posterior coronary territory. Unlike traditional CABG, the longitudinal axis and apex of the heart cannot be xe2x80x9cverticalizedxe2x80x9d with respect to the surgical table and retracted chest cavity tending to facilitate access to the posterior territory. Performing port access surgery remotely through a number of small ports tends to be difficult, at times leading to unwanted tissue dissection that requires the conversion to a full sternotomy in order to complete the surgical procedure.
In recent years, the drive for less-invasive and cost-effective surgical approaches and apparatus has placed emphasis on cardiac surgery as well. However, unlike other organ surgeries, gall bladder for instance, the beating motion of the heart tends to complicate the surgical intervention.
In minimally invasive direct coronary artery bypass graft surgery (MIDCAB), ECC is avoided and coronary artery revascularization is performed directly on the beating heart with the help of a mechanical coronary artery stabilizer, through a mini-sternotomy or mini-thoracotomy incision. This surgical approach allows access to only one or two of the anterior arteries of the heart, most commonly the left anterior descending artery (LAD). Demographically, only 5-15% of the cardiac surgery population is afflicted with single vessel disease; the majority of cardiac patients (70%) suffer from triple vessel disease, whereby at least one artery on each of the anterior, inferior and posterior territories of the heart requires a bypass graft. As a result, this approach has also been referred to as xe2x80x9climited access bypass surgeryxe2x80x9d. Moreover, the MIDCAB thoracotomy incision to access the beating heart has been discovered to be more painful and less tolerated by patients than originally anticipated, especially in younger patients.
More recently, the beating heart approach through a sternotomy incision has been adopted tending to facilitate positioning of the beating heart within the retracted chest cavity and tending to facilitate grafting of the difficult to access posterior arteries. Mechanical coronary artery stabilizers have been developed to immobilize a portion of the beating heart surface proximate to the target artery during the distal anastomosis phase of the surgery. A median sternotomy is desirable since it tends to allow the apex of the beating heart to clear the retracted ribcage as the heart""s longitudinal axis is xe2x80x9cverticalizedxe2x80x9d in order to expose the posterior coronary territory. In some patients, verticalization of a beating heart is not well tolerated and may lead to hemodynamic instability during the surgical procedure. At times, this unnatural xe2x80x9cverticalizedxe2x80x9d orientation of the beating heart may be attained with some degree of atrial or ventricular distortion, and even some degree of valvular dysfunction and regurgitation. Moreover, although the beating heart approach achieves the elimination of the cardio-pulmonary machine, the sternotomy incision with its associated complications is retained in this approach.
Percutaneous transluminal angioplasty (PCTA) or Coronary Stenting are intraluminal surgical procedures which achieve coronary artery revascularization through the enlarging of restricted vessels by balloon angioplasty (PTCA) and in some cases also supplemented by the scaffolding effect of the tubular mesh stent. Sternotomy incisions and ECC are avoided since the entire procedure takes place through the patient""s artery. However, the high incidence of restenosis associated with PTCA, and its generally low endorsement in the treatment of triple vessel disease does not make this procedure suitable to the majority of cardiac surgery patients that require coronary artery revascularization. Other emerging technologies, such as Transmyocardial Revascularization (TMR) or Percutaneous Myocardial Revascularization (PMR) are reserved for surgically non-reconstructible coronary artery disease.
It would therefore be advantageous to have a surgical apparatus and associated surgical approach which maintains, as much as possible, the normal anatomic position and orientation of the heart during a surgical intervention. One aspect of the present invention aims to provide access to the posterior coronary territory of a beating heart during CABG surgery, without the need for a sternotomy incision, and while the longitudinal axis of the beating heart is maintained as much as possible in its natural substantially-horizontal anatomic orientation. The combination of the beating heart approach with a surgical approach attempting to access all coronary territories without the need for either a sternotomy or thoracotomy incision would therefore offer distinct advantages in reducing the risk of complications and minimizing the surgical scaring normally associated with current CABG surgeries.
A percutaneous incision in the abdominal region below the patient""s ribcage, and the subsequent creation of a trans-abdominal, trans-diaphragmatic tunnel may provide a suitable surgical approach to attain the patient""s thoracic cavity. The patient""s heart and internal cardiac tissue may then be accessed by a variety of surgical instruments extending through an access cannula placed in said trans-abdominal tunnel and extending beyond an anatomic barrier, such as the patient""s diaphragm. A number of surgical manipulations and interventions may then be performed by selected surgical instruments on the target tissue such as the patient""s heart or other internal cardiac tissue. Internal cardiac tissue includes but is not limited to the pericardium, epicardium, myocardium, endocardium, apex of the heart, ascending and descending aorta, vena cava, coronary arteries and veins, internal thoracic arteries, pleurae, endothoracic fascia, and other like anatomic tissue. One aspect of the present invention describes a surgical apparatus that allows the manipulation and positioning of a beating heart within the patient""s thoracic cavity, along with the deployment within the patient""s thoracic cavity of coronary stabilizers that serve to immobilize a portion of said beating heart proximate to a target coronary artery, through a trans-abdominal tunnel. This aims to allow at least some surgical interventions associated with coronary artery revascularization to be performed without the invasiveness of ECC and without having to perform bone-cutting or bone splitting incisions such as sternotomy, intercostal thoracotomy with spreading of adjacent ribs, or other like surgical incisions. This tends to provide a closed chest surgical approach to perform cardiac interventions. The arteriotomy and distal coronary anastomosis, although may be performed through a number of intercostal ports not requiring the bone splitting or bone spreading incisions, are also preferably performed through the trans-abdominal, trans-diaphragmatic tunnel. In the present invention, the term xe2x80x9cclosed chestxe2x80x9d will refer to surgical procedures which keep the patient""s thoracic structure intact.
It is therefore an object of the present invention to provide a surgical apparatus and method that enable coronary artery revascularization on the beating heart without the need for ECC, and without having to spread apart the patient""s thoracic bone structure through a sternotomy, thoracotomy or other like incision.
It is a another object of the present invention to provide a surgical apparatus and method that enable cardiac surgical interventions, not restricted to only beating heart CABG, to be performed without having to spread apart the patient""s thoracic bone structure through a sternotomy, thoracotomy or other like incision.
Some of the aspects of the present invention may also apply to other types of surgery, such as laparoscopic, endoscopic, or thoracoscopic surgery, whereby surgery is performed on target tissue contained within an internal body cavity that is accessed by surgical instrument disposed through an access cannula. Here the manipulation of surgical instruments during a surgical intervention performed through an access cannula may be better effectuated if said instruments are engaged with an internal joint within said cannula. Also it may be desirable in such surgical procedures to be able to secure said joint and maintain engaged instrument in a desired fixed position and orientation relative to the access cannula, at least for a part of the surgical procedure. The surgical procedure may also be further improved if the access cannula is also engaged with a movable joint connected to a stable surgical platform, whereby said joint may also be secured by a tightening means to maintain access cannula in a desired fixed position and orientation relative to patient and surgical table. The access cannula may also serve to introduce into the internal cavity surgical aids which may not engage target tissue during a surgical intervention, but help facilitate a surgery through their installation. For example, a camera lens or a fiber-optic bundle to provide light.
It is a further object of the present invention to provide a surgical apparatus and method that tends to facilitate endoscopic surgery, more specifically endoscopic surgery where a surgical procedure is to be performed within an internal body cavity beyond an anatomic barrier, through the use of surgical instruments introduced therein through an access cannula.
These and other objects of the present invention will become apparent from the description of the present invention and its preferred embodiments which follows.
The present invention provides an access cannula with a substantially open proximal end and a substantially open distal end, and at least one substantially hollow passageway extending from said open proximal end to said open distal end. The outer surface of the access cannula is preferably engaged with at least one anatomic barrier. Target tissue is located in an internal body cavity or region downstream of an anatomic barrier and generally beyond the distal end of access cannula. The access cannula provides access, beyond at least one anatomic barrier, to a variety of surgical instruments which are able to extend beyond the distal end of access cannula. Some instruments will engage target tissue during at least a part of the surgical procedure they are intended for.
Instruments are preferably engaged with access cannula through an internal joint which may provide a number of motion degrees of freedom to said instrument when they are engaged with access cannula. Surgical instruments may be demountably engaged with access cannula, or permanently engaged with respect to access cannula, or may even be engaged with access cannula via a cartridge in which they are disposed. Surgical instruments may be secured in a desired position and orientation relative to access cannula and relative to a target tissue through a tightening element.
Proximal end of surgical instruments extend beyond proximal open end of access cannula, thereby allowing the surgeon to manipulate said proximal ends. Proximal manipulations on a proximal end of a surgical instrument, usually applied extracorporeally by the surgeon, are linked through an engagement with an internal joint to distal movements of a distal end of said instrument within an internal body cavity.
The hollow passageway through an access cannula may be partitioned to create additional segregated passageways. Alternatively, substantially longitudinal access lumens extending generally from proximal end to the distal end may also be provided for engagement with surgical aids. Seal members may be provided across hollow passageways in order to maintain an internal body cavity, situated downstream of an anatomic barrier, at a different ambient condition than an extracorporeal region.
Vision ports such as stereoscopic camera lenses, that transmit images to the surgeon so that closed chest interventions may be remotely performed, are deployed within an internal body cavity either through a transabdominal tunnel or through additional intercostal port incisions in the patient""s chest. Carbon dioxide is used to displace abdominal organs during the deployment of surgical instruments used to create a transabdominal tunnel. Passages in the access cannula are also provided for the channeling of carbon dioxide gas into the pleural space.
Access cannula may be manipulated and held by hand, but it is preferable to have it engaged with a stable support such as a surgical table. A surgical arm enables access cannula to be reoriented and repositioned relative to a surgical table and also the patient""s body. Once a desired position is achieved, access cannula is secured into position.
In performing a beating heart surgery, a variety of different surgical instruments may be engaged with access cannula, some are deployed alone while others may be deployed in combination. In one aspect of the invention aimed to perform coronary artery revascularization on a beating heart, a surgical apparatus is provided comprising an access cannula which is inserted through the diaphragm of the patient such that the distal end of cannula attains the pleural space. A heart manipulator, engaged with an internal joint inside the hollow passageway of access cannula engages the surface of the beating heart, preferably the apex, when said distal end of heart manipulator extends beyond the distal end of access cannula. Once a desired orientation and position of the beating heart is achieved, its position is secured relative to access cannula by an internal joint. A coronary stabilizer, also engaged with an internal joint inside the hollow passageway of the access cannula is then subsequently deployed. Coronary stabilizer is placed on a portion of the surface of a beating heart proximal to a target artery in need of anastomosis. The invention allows the surgeon to position a contact face on the surface of the beating heart and apply a gradual mechanical force until the portion of myocardium around the target artery is stabilized and rendered substantially motionless relative to cannula, while the rest of the heart continues to beat. The coronary stabilizer is subsequently secured. In approaching other vessels of the heart, as in multi-vessel CABG surgery, the access cannula may be rotated about its centerline relative to the heart and body in order to optimize the position of the heart manipulator and coronary stabilizer relative to the target heart tissue. The surgical apparatus aims to provide a way of accessing all territories of the heart by the deployment of an access cannula, and subsequent deployment of a heart manipulator and a coronary stabilizer relative to access cannula and to each other.
Another aspect of the invention describes a surgical method in which the surgical apparatus may be used to perform coronary artery revascularization on the beating heart through an access cannula inserted through a transabdominal approach. This surgical method avoids the ECC and is less invasive for the patient. This surgical method also avoids the need for cutting the patient""s ribcage, or spreading apart ribcage or removing part of patient""s rib in order to access the patient""s heart such as is the case with conventional CABG surgery or beating heart surgery performed through a sternotomy, thoracotomy, or other like incisions.